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Just a heads up for those trying to find plugs, if you're CONUS, there's always RockAuto. They don't always have full availability, but for those heat ranges they do stock, they give a pretty decent price at just under $25/each. Watch out for shipping though. To my house, it's $4 for 4 Densos.
NGK R6725: available in 9 and 10
Denso IRE-01: available in 10.5, 11, and 11.5
But as always, support your vendors, lol.
Gilgamesh, how are those IRL01s? That's a killer deal you got.
Gilgamesh, how are those IRL01s? That's a killer deal you got.
I have not used them just yet, I will swap them in when more tuning gets done on my car. Right now its too rich and I just drive it casually.
NGK also makes a copper/Nickel surface discharge plug. The longevity vs cost of the plug may not work out for everyone.
They are $16.45 on rock auto.
The 10 heat range is $18.66 on Amazon w/ prime.
R6601-11
Center Electrode Core Material Copper Core
Center Electrode Tip Material Nickel
Gap Size 0.016 in
Hex Size 5/8"
Insulator Height ISO
Manufacturer Heat Range 11
Additional Info 5K Ohm
Seat Type Gasket
Reach 19mm
Thread Diameter 14 MM
Ground Electrode Tip Design Surface Discharge Type
Ground Configuration Surface Discharge
Ground Electrode Core Material Nickel Core
Yes so resistor is recommended due to emi noise, what about using resistor caps on non-resistor plugs?
And the shorter reach causes carbon deposits that can lead to preignition and also cause the horizontal cracks on the plug holes? Is that it? Is this confirmed or theorized?
And the shorter reach causes carbon deposits that can lead to preignition and also cause the horizontal cracks on the plug holes? Is that it? Is this confirmed or theorized?
The horizontal cracks in the rotor housings are from thermal expansion.
The shorter reach spark plugs are said to be a possible cause of detonation in the Mazda Competition catalog.
Mazda
IG-3
NGK Spark Plugs
We offer a variety of NGK stock and racing spark plugs for rotary and piston
applications.
n
Racing Plugs (R6725 and T813JN-13 series) are recommended for all
rotary engines that are being used in a racing application. The R6725
series plugs are available in the following heat ranges
*
: 10.5, 11.0 and
11.5. The T813JN-13 is a 13.0 heat range plug.
n
The NGK “EGV” plug provides a number of different heat ranges
*
: 8.0, 9.0,
10.0 and 11.0. However, the reach of the “EGV” plug is not as long as that
of the racing plugs or the stock plugs. This shorter “reach” means that its flash-
front is not as close to the combustion chamber, and therefore may cost horse-
power. It also leaves some threads in the spark plug hole exposed, where
carbon can build up, resulting in possible detonation. Installation and removal
of these plugs on 1981 and later engines requires use of a special thin-wall
spark plug socket because of a protrusion that restricts the installation of the
wrong type of plug. A spark plug socket may be machined down to the
correct diameter, or the protrusion may be ground off.
n
The stock plug for the 1993-95 RX7 Twin-Turbo (NGK Part #BUR9EQP) is a
platinum plug that can be used for stock or mildly ported engines. The
“9.0” is the coldest heat range it comes in. This plug is recommended for
stock-ported 12A and 13B engines (SCCA IT class)
In another spark plug thread I read someone opine there is no benefit to running the colder plug in the Trailing position- I will try to find that thread and post this as well.
-edit-
found it was this thread, 1 page back.
gxl90rx7
its dumb to run all 9's and think you are better off than running factory plugs. the trailing is naturally hotter, if you went from 7 to 9 in the leading only you didnt change anything. and i would not run the 3292 only because it has no resistor and can cause pickup noise which is instant engine killer. if you wnat your engine to last every little bit counts and it adds up
Mazda
NGK Part #BUR9EQP (platinum)
May also be used for 1986-91 RX7 & SCCA
“IT” class (12A & 13B-ALL) (leading and
trailing).
This is probably what started people running 9s all the way around in the FD as well.
wow I don't know how I missed this thread. Thanks for all the replies!
I just bought 6 of Denso (5720) IRE01-31 Iridium Racing Spark Plugs. Is this the one with the correct length and resistor, and comes appropriately gaped so all I need to do is pop them in?
These will be going into single turbo 20b making around 700whp, on its way to 900whp with WI.
I also see NGK (3857) R6725-105 Racing Spark Plug being recommended by many members..
I also see NGK R7420 being recommended, but it isn't flat surface from the internet pictures..
I don't mind spending what I need to spend on the plugs to save my housings.. what do you guys think would be the consensus best plug for 300whp/rotor application?
Last edited by stickmantijuana; May 22, 2017 at 11:37 PM.
wow I don't know how I missed this thread. Thanks for all the replies!
I just bought 6 of Denso (5720) IRE01-31 Iridium Racing Spark Plugs. Is this the one with the correct length and resistor, and comes appropriately gaped so all I need to do is pop them in?
These will be going into single turbo 20b making around 700whp, on its way to 900whp with WI.
I also see NGK (3857) R6725-105 Racing Spark Plug being recommended by many members..
I also see NGK R7420 being recommended, but it isn't flat surface from the internet pictures..
I don't mind spending what I need to spend on the plugs to save my housings.. what do you guys think would be the consensus best plug for 300whp/rotor application?
As far as the NGK's go the R6725 and R7420 are the same plug other then the R6725 being Platinum and R7420 being Iridium.
what do you guys think would be the consensus best plug for 300whp/rotor application?
